Abstract:
Water flow and sedimentation beneath the McMurdo Ice Shelf south of Ross Island was investigated by using a hot water drilling system to melt access holes through the ice shelf allowing measurements and samples to be taken from the water column and sea floor beneath. The water depth, sub-seafloor topography (3.5 kHz transducer), current speed and direction profiles through the water column, ... conductivity, temperature and water samples for chemistry and suspended particulate matter was all measured through a tidal cycle before sampling the sea floor. 48 mm diameter sediment cores (at least three from each site >50cm long) and grab samples from the top 3-5cm of the sea floor were collected after water column measurements. Two holes were drilled, 5 and 12 kilometers east of Scott Base. The sites were relatively remote, being covered by ice 70 and 143 m thick and with sea floor 926 and 923 m below sea level. A third site was used south of Scott Base where current to 400 m depth was measured continuously over 3-4 weeks.